adds round telemetry support

src/lib/ui/components/RoundTelemetry.svelte

@@ -0,0 +1,19 @@
+<script lang="ts">
+    import { telemetryByServer, uiNow } from '$ui/stores/servers.js';
+    import { elapsedSince } from '$ui/duration.js';
+    let { name }: { name: string } = $props();
+    let report = $derived($telemetryByServer.get(name));
+</script>
+
+{#if report}
+    <div class="round" aria-live="polite">
+        <strong>Round {report.round}</strong>
+        <span title={report.receivedAt}>Last reported {elapsedSince(report.receivedAt, $uiNow)} ago · {report.players} players</span>
+    </div>
+{/if}
+
+<style>
+    .round { display: flex; flex-wrap: wrap; align-items: baseline; gap: var(--space-2); }
+    strong { color: var(--text-primary); font-family: var(--font-mono); }
+    span { color: var(--text-tertiary); font-size: var(--text-xs); }
+</style>

src/lib/ui/components/ServerCard.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+    import RoundTelemetry from './RoundTelemetry.svelte';
     import type { RosterPlayer, Health } from '$ui/stores/servers.js';
     import { uiNow } from '$ui/stores/servers.js';
     import { gametypeLabel } from '$ui/gametype.js';
@@ -118,6 +119,8 @@
         {/if}
     </div>
 
+    <RoundTelemetry {name} />
+
     {#if showTiming}
         <div class="timing">
             {#if activeElapsed}

src/lib/ui/stores/servers.ts

@@ -1,5 +1,8 @@
 import { writable, readonly } from 'svelte/store';
 import { browser } from '$app/environment';
+import type { RoundTelemetry } from '$lib/telemetry.js';
+
+export const telemetryByServer = writable<Map<string, RoundTelemetry>>(new Map());
 
 export interface RosterPlayer {
     num: number | null;
@@ -49,6 +52,14 @@ let source: EventSource | null = null;
 export function startServerStream(): void {
     if (!browser || source) return;
     source = new EventSource('/api/events/servers');
+    source.addEventListener('server-telemetry', (evt) => {
+        const data = JSON.parse((evt as MessageEvent).data) as { entries: RoundTelemetry[]; snapshot?: boolean };
+        telemetryByServer.update((previous) => {
+            const next = data.snapshot ? new Map<string, RoundTelemetry>() : new Map(previous);
+            for (const entry of data.entries) next.set(entry.server, entry);
+            return next;
+        });
+    });
     source.addEventListener('server-status', (evt) => {
         const data = JSON.parse((evt as MessageEvent).data) as { entries: ServerStatus[] };
         statusByServer.update(() => {